Snowshoes have been used for more than 1,000 years to move in snow and on ice. Commander Peary already used snowshoes in his conquest of the North Pole. Originally, rawhide straps were used for the webbing of the snowshoes with the bindings formed by a number of loose straps.
One must differentiate between snowshoe equipment, cross-country ski equipment, downhill ski equipment and, more recently, snow board equipment. Cross-country ski equipment involves relatively light-weight narrow skis and relatively light-weight cross-country shoes for use with bindings specifically designed for the cross-country skis and shoes (for example, U.S. Pat. No. 4,142,734). Downhill ski equipment involves relatively wider and heavier skis than cross-country skis, and relatively heavy boots to provide support which are made at present from plastic materials with relatively thick standard soles for use with ski bindings, normally with safety bindings specifically designed for these types of boots, of which a large variety exist (for example, U.S. Pat. Nos. 1,815,168; 2,072,477; 4,846,492; 4,871,186 and 4,893,831). Snow boards are of more recent origin, whereby both feet rest on a single board with at least one step-in binding for one boot (for example, U.S. Pat. No. 4,973,073). Snowshoes, on the other hand, are used to walk, respectively, run on snow and with the use of crampons can be used even to climb fairly steep inclines on snow and/or icy surfaces Because of the different functions of these various equipments, their design including bindings and footwear are specific to meet the differing demands and therefore are normally not applicable interchangeably. Relatively complicated bindings have been proposed heretofore to permit use for downhill and cross-country skiing, as exemplified by U.S. Pat. Nos. 2,072,477; 4,002,354; 4,152,009 and 4,674,766. However, they have found relatively little acceptance so far in the marketplace where single-use equipment is preferred.
Early snowshoe bindings utilizing leather straps which flopped around and hung loose, were rather cumbersome in use. Moreover, the lacing of the toe-cord with the use of rawhide or neoprene straps imposed severe limitations from a design point of view because of sag in the fore and aft directions. Over the years, snowshoes have undergone changes. For example, in lieu of the wooden frame, metal frames even with solid decking have already been proposed (U.S. Pat. No. 4,041,621). Additionally, to improve the usability of the snowshoe, a pivotal arrangement of the footwear has been proposed, for example, in U.S. Pat. Nos. 1,054,352; 2,420,621; 2,738,596; 2,987,834; 3,344,538; 3,802,100 and 4,259,793. Various snowshoe bindings have also been proposed heretofore to improve convenience and/or achieve improved performance as exemplified, for example, by U.S. Pat. Nos. 1,156,174; 1,523,222; 2,385,944; 2,821,031; 2,987,834; 3,555,707; 3,744,162; 3,885,327; 3,965,584 and 4,259,793. However, certain limitations still continue to beset the presently available snowshoes which involve, inter alia, problems of getting in and out of the snowshoe bindings, even to the point where snowshoe enthusiasts become sufficiently disenchanted to drop the snowshoe activities.
Sag in the webbing or lacing also poses a problem which affects the usefulness of the snowshoe Pads of imperforate flexible material have already been proposed in U.S. Pat. No. 4,259,793 to prevent the snowshoe from deeply penetrating the snow; however, the binding of this patent continues to be supported by webbing.
The need for crampons with snowshoes depends on the snow, respectively, ice conditions of the travelled surfaces as well as on the steepness of the terrain and whether one wants to climb or glissade downhill.
It is well known that when climbing, crampons are very useful. There are times, however, when snowshoes are easier to control without crampons, such as when glissading downhill in a semi-telemark-like technique. When one is using crampons, performance and snowshoe control can also be enhanced using a specific type of crampon that is optimally suited for the type of snow conditions or type of snowshoe use. For example, one type of crampon with short teeth is best suited for fine-grain, compact density snow, while another type--with much longer teeth--is better suited for loose grain or loose, granular-type snow conditions. The length of the teeth are also a function of the steepness of the terrain: the longer the teeth, the better the grip into the snow for more resistance against the resultant forces of gravity. It is therefore necessary, when climbing mountains, to use short teeth crampons at the base and then switch to long-toothed crampons near the summit Heretofore, rapid change in the cold has been difficult or impossible depending on the degree of discomfort the user is willing to endure. Further, different types of snowshoe activities suggest the use of different crampon materials Plated steel crampons are well-suited for public utility workers who use snowshoes because durability and reliability are of key importance. On the other hand, snowshoe racers prefer the use of aluminum crampons, trading-off long-term durability for the immediate benefits of weight reduction and running speed. Being able to optimize crampon type for different snowshoe uses, without a long assembly and disassembly period, can be beneficial to the users. Heretofore, the removal of crampons, for example, for glissading has been very difficult in the cold with wrenches and screwdrivers, often requiring the removal of gloves. Often, because of the inherent difficulties of removing crampons, snowshoers will forego their removal and therefore sacrifice efficient descent. The prior art crampon attachment thus represented a serious drawback in the optimization of crampon use.
Another problem with the prior art snowshoe bindings resided in the inadequate support, particularly lateral support, during traversing across hills and aggressive scrambling where the swing-weight (polar moment of inertia) does not follow the inertial resistance (changes in angular momentum) of the human leg and thus becomes unstable dynamically and is therefore less controllable to the user.
A further shortcoming of some prior art snowshoe bindings can be found in the strap arrangements with or without the use of buckles which permit a cinching only in a non-ergonomic manner.